HIGH ENERGY LONG LIFE BATTERY R&D

THE NAVY HAS A NEED FOR RECHARGEABLE BATTERIES WITH ENERGY DENSITIES FAR SUPERIOR TO THOSE OF ORDINARY LITHIUM SYSTEMS FOR POTENTIAL USE IN UNMANNED AIR VEHICLES. THERE IS A CLEARLY ESTABLISHED NEED FOR RECHARGEABLE HIGH ENERGY CELLS AND BATTERIES FOR SPACE POWER TECHNOLOGY. THIS CALLS FOR MORE ENERGETIC LITHIUM SYSTEMS THAT HAVE BEEN STUDIED SO FAR, WITH PRACTICAL ENERGY DENSITIES IN EXCESS OF 250 WH/KG. A NEW APPROACH IS PROPOSED TOWARDS AMBIENT TEMPERATURE HIGH ENERGY LITHIUM BATTERIES BASED ON TWO NEW KEY IDEAS. ONE IS TO USE REDUCIBLE CATHODES INSTEAD OF INTERCALATION MATERIALS AND THE OTHER TO EMPLOY INORGANIC ELECTROLYTES AS A BASIS FOR HIGH RATE CAPABILITY AND A GREATER LONG RANGE STABILITY. REDUCIBLE CATHODES OFFER HIGHER ENERGY AND POWER DENSITIES OVER A WIDER TEMPERATURE RANGE AND SHOULD BE CAPABLE OF LONGER CYCLE LIVES AS WELL. NEW CATHODES ARE PROPOSED BECAUSE OF THEIR PARTICULARLY HIGH ENERGY DENSITY AND LOW SOLUBILITY IN THE ELECTROLYTE WHICH WOULD BE THE BASIS FOR GREATER STABILITY NEEDED FOR A LONG CYCLE LIFE. THEORETICAL ENERGY DENSISITES IN EXCESS OF 1300 WH/KG ARE INVOLVED IN THESE REDUCIBLE CATHODE SYSTEMS COMPARED TO ONLY 480-700 AVAILABLE FROM THE BEST INSERTION TYPES. THUS, THE PROPOSED PROGRAM REPRESENTS A NEW APPROACH AND A CLEAR DEPARTURE FROM RECENT TRENDS IN THIS FIELD.